https://www.polygon.com/2018/6/19/17478476/playerunknowns-battlegrounds-sales-pubg-number-of-players

PlayerUnknown’s Battlegrounds has amassed more than 400 million players across all currently available platforms, developer PUBG Corp. announced today. That figure includes more than 50 million copies of the game sold on Windows PC and Xbox One, the company said.

That means that somewhere around 350 million of those total players are playing the game on mobile devices. PUBG is available on Android and iOS as a free-to-download game.